Because a power conversion device using switching of a power semiconductor element has high conversion efficiency, the power conversion device is used widely for consumer use, a vehicle, a railroad, and a transformation facility. Because the power semiconductor element generates heat by energization, high heat dissipation is required. In addition, the power semiconductor element is sealed with resin or gel for insulation.
A structure for mounting the power semiconductor element on a metal body provided with a flow channel and sealing the power semiconductor element with the resin is disclosed in PTL 1.